It has been attempted for some time to provide containers or cages for breeding fish in natural bodies of water. These containers have walls which allow water to pass, such as walls of netting, for the purpose of renewing the water content and sweeping out the excrements produced by the metabolism of the fish. They must be kept normally at the water surface, so that the fish may be fed and their breeding may be controlled. Fish can be introduced into such containers, they can be fed, and their growth can be controlled, so that they can be harvested at the proper time. While this method of breeding is not adapted to all kinds of fish, it is highly effective for those kinds to which it is adapted, and permits providing fish food more conveniently and economically than afforded by normal fishing techniques.
However, such breeding containers must be protected against excessively violent wave motion, such as caused by storms, which would cause heavy damage or destruction of the container. For this purpose, it has been proposed to place the fish-breeding containers near the shore in partially enclosed bodies of water, such as in bays or fjords, in which the wave motion is moderate even during storms on the open sea. However, locating the containers near the shore creates severe pollution, due to the metabolism of the fish and to the feed provided to them, so that this method has been practically abandoned.
Pollution can be avoided by locating the containers in the open sea, whereby the waves and currents sweep out the pollution and disperse it, the operation of the containers being controlled from a near-by vessel. However, in this case, they must be safeguarded against severe wave motion and therefore, if a storm approaches, they must be lowered below the water surface while the control vessel finds refuge in a harbor. All these proposals, however, rely on pulleys or, in general, rotatable guides located at the bottom of the sea. In time, marine fouling, such as barnacles, grows on said devices and renders them inoperative. Therefore, this method of breeding fish in containers in the open sea has not been successful, so far.
It is a purpose of this invention to provide an apparatus and a method for breeding fish in containers in the open sea.
It is another purpose to provide such an apparatus and method which are proof against the marine fouling of any elements thereof.
It is a further purpose to provide such a method and apparatus that afford complete and easy control of the breeding of the fish.
It is a still further purpose to provide such a method and apparatus that permit lowering the breeding containers below the water surface, when needed, under full control and at the desired speed.
It is a still further purpose to provide such a method and apparatus that permit raising the fish-breeding container, when the need to keep it underwater has passed, with the desired speed and under control, and to keep it floating under normal conditions.
Other purposes and advantages of the invention will appear, as the description proceeds.